Hi Darksiege, didn’t know you were diabetic.
The reason why people living with diabetes need special socks is due to the desensitising of nerve vessels due to elevated (sometimes prolonged) blood glucose. This makes cuts and bruises on the foot/legs harder to detect and infection more likely. Due to the damage to nerves, most of these infections are not discovered or left untreated, which could be dangerous.
There are no dangers with wearing tight socks (or normal socks for that matter), provided you check your foot/leg for cuts and bruises after your ride/day out at least once a week.
Tight socks are good for the circulation when you’re sitting down for a long time, or if you have cardiovascular issues where slow blood flow may be an issue (e.g. thrombosis).
Hope this is of help, if you need more information on living with diabetes, feel free to PM me and I am happy to dump truck loads of information on you.
